Various types of driving assistance systems were proposed in the past. For instance, a system described in a US published patent application No. US2003/0060936 A1 includes a controller, at least one actuator and a data acquisition system for obtaining data related to a status of a vehicle and an environment in a field around the vehicle. The controller determines a future environment in the field around the vehicle using the acquired data, and generates an operator response plan in response to the determined future environment. The plan prompts the operator to operate the vehicle in a desired manner. The actuator is coupled to a driver controlled input device to mechanically affect operation of the input device in a manner that prompts, via a haptic input to the driver to operate the vehicle in the desired manner.
Another example of such systems is proposed in US published patent application No. US2003/0233187 A1. This system transmits a risk associated with a host vehicle (or alternatively called an own vehicle) to a driver by a reaction force input applied to an accelerator pedal. Based on the position of the accelerator pedal, an inter-vehicle distance between the host vehicle and another vehicle in a field around the vehicle.
Still another example of such systems is proposed in US published patent application US2003/0135317 A1 (Japanese counterpart JP2003-205760 A). This system transmits a risk associated with a vehicle to a driver by a reaction force input via an accelerator pedal. The reaction force input is exponentially proportional to the risk so that the driver is kept informed of the progress of the risk.
These conventional systems, however, do not transmit different levels of risk to the driver in a sufficiently clear and discrete manner because the reaction force input via the accelerator pedal varies continuously with the risk.
Accordingly, there is a need for a method and system that can transmit different levels of risk around a vehicle to a driver in a clear and distinct manner.